1. Field of the Invention
The present invention relates generally to ink-jet printing and, more specifically to a method and mechanism for cleaning a belt used in the transport of print media through a printing zone.
2. Description of Related Art
The art of ink-jet technology is relatively well developed. Commercial products such as computer printers, graphics plotters, copiers, and facsimile machines employ ink-jet technology for producing hard copy. The basics of this technology are disclosed, for example, in various articles in the Hewlett-Packard Journal, Vol. 36, No. 5 (May 1985), Vol. 39, No. 4 (August 1988), Vol. 39, No. 5 (October 1988), Vol. 43, No. 4 (August 1992), Vol. 43, No. 6 (December 1992) and Vol. 45, No. 1 (February 1994) editions. Ink-jet devices are also described by W. J. Lloyd and H. T. Taub in Output Hardcopy [sic] Devices, chapter 13 (Ed. R. C. Durbeck and S. Sherr, Academic Press, San Diego, 198).
FIG. 1 (Prior Art) is a schematic depiction of an ink-jet hard copy apparatus 10. A writing instrument 12 is provided with a printhead 14 having drop generators including nozzles for ejecting ink droplets onto an adjacently positioned print medium, e.g., a sheet of paper 16, in the apparatus printing zone 34. An endless-loop belt 32 is one type of known manner printing zone input-output paper transport. A motor 33 having a drive shaft 30 is used to drive a gear train. 35 coupled to a belt pulley 38 mounted on an fixed axle 39. A biased idler wheel 40 provides appropriate tensioning of the belt 32. The belt rides over a platen 36 in the print zone 34; the platen is described in detail hereinafter, but is associated with a known manner vacuum induction system 37. The paper sheet 16 is picked from an input supply (not shown) and its leading edge 54 is delivered to a guide 50, 52 where a pinch wheel 42 in contact with the belt 32 takes over and acts to transport the paper sheet 16 through the printing zone 34 (the paper path is represented by arrow 31). Downstream of the printing zone 34, an output roller 44 in contact with the belt 32 receives the leading edge 54 of the paper sheet 16 and continues the paper transport until the trailing edge 55 of the now printed page is released. The carriage scanning axis is conventionally designated the x-axis, the print media transit axis is designated I, the y-axis, and the printhead firing direction is designated the z-axis. For convenience in describing the art and the present invention, all types of ink-jet hard copy apparatus are sometimes hereinafter referred to as xe2x80x9cprinters;xe2x80x9d all types, sizes, and compositions of print mediaxe2x80x94including non-traditional printing media such as polymeric transparencies, cloth fabric, mylar, and the likexe2x80x94are also referred to simply as xe2x80x9cpaper;xe2x80x9d all compositions of colorants are sometimes referred to as xe2x80x9cink;xe2x80x9d and all embodiments of an ink-jet writing instruments are simply referred to as a xe2x80x9cpen;xe2x80x9d no limitation on the scope of the invention is intended nor should any be implied.
During printing operations, ink deposits or aerosol mixtures of ink and paper dust collect on the belt and platen. Once on the belt, ink begins transferring onto subsequent sheets as well as internal components of the print mechanism. This can cause print defects and unattractive splotches on the reverse side of the print, Thus, there is a need for paper transport belt cleaning mechanisms.
In one basic aspect, the present invention provides a cleaning medium for feeding through an inkjet apparatus print zone to clean a paper transport belt, including: an absorbent material layer having a surface for frictional contact with the belt such that friction between the absorbent material layer and the belt scrubs ink from the belt and ink is absorbed into the material layer.
In another basic aspect, the present invention provides method for cleaning an inkjet paper, endless loop, transport belt including the steps of: feeding a cleaning medium from an input into a print zone wherein the cleaning medium is in surface-to-surface contact with the belt; passing the cleaning medium through the print zone such that the belt is in contact there against; absorbing ink from the belt into the cleaning medium; and releasing the cleaning medium from the print zone.
In another basic aspect, the present invention provides ink-jet hard copy system including: an endless loop belt for conveying media from an input through a printing zone to an output; an inkjet writing instrument positioned for depositing ink in the printing zone; a feed device for guiding media from the input to the belt and for selectively holding a sheet of media in the printing zone irrespective of movement of the belt; and at least one cleaning medium associated with the feed device for selectively scrubbing the belt.
In another basic aspect, the present invention provides cleaning medium for cleaning a transport apparatus for sheet material, including: a cleaning material construct having at least one surface for contact with components of the sheet transport device wherein the construct is fed into the sheet transport device in like manner as the sheet material.
Some advantages of the present invention are:
it dissolves ink and absorbs ink from the belt and other components in the paper path that can be contaminated;
it scrubs the belt of contaminants that can affect its functionality;
it requires no additional mechanisms to be incorporated into the hard copy apparatus;
it assists in removing contaminants from the platen surface below the belt; and
disposability makes the invention a low cost, reliable solution.
The foregoing summary and list of advantages is not intended by the inventors to be an inclusive list of all the aspects, objects, advantages and features of the present invention nor should any limitation on the scope of the invention be implied therefrom. This Summary is provided in accordance with the mandate of 37 C.F.R. 1.73 and M.P.E.P. 608.0(d) merely to apprise the public, and more especially those interested in the particular art to which the invention relates, of the nature of the invention in order to be of assistance in aiding ready understanding of the patent in future searches. Other objects, features and advantages of the present invention will become apparent upon consideration of the following explanation and the accompanying drawings, in which like reference designations represent like features throughout the drawings.